Let me show you How to Make a Rainbow Heart Surprise Inside Cake. This loaf cake with a rainbow heart in the middle looks difficult but is really quite simple to make.
The concept of surprise-inside cakes was developed by food blogger Amanda Rettke. This is also a review of her cookbook called Surprise-Inside Cakes.
WHY I LOVE THIS HOW TO MAKE A RAINBOW HEART SURPRISE INSIDE CAKE
• This cake is super moist and fluffy! It is quite a nice surprise when you slice into it!
• Super colorful and perfect for a birthday, Valentine's Day, any special occasion, or an anniversary!
• It may seem super difficult to make, but when you figure out how to make it, it is not hard at all!
• Delicious ingredients like the white cake and frosting.
• A special cake pan is not required for this recipe, just a loaf pan! You don't even need a heart-shaped pan.
• The heart-shaped cake in the middle makes it so adorable! It will be the cutest cake you have ever made.
• No need to frost the cake nicely! It doesn't require special piping skills, just frost it on with a spatula!
• If you love this cake, you will love Amanda's cookbook! She has so many cute surprise-inside cakes for all the holidays.
White Cake: Use a white box cake mix from your local grocery store. Feel free to make the white cake layers with a homemade white cake recipe! For example, you can use my "Classic White Cake Made from Scratch" recipe, it is delicious!
Food coloring: I recommend using food coloring gel. You will need 5 colors: red, orange, yellow, green, and blue. However, if you don't want it rainbow, feel free to use whatever colors you want!
Shortening/Butter: The frosting is made with vegetable shortening (Crisco) and room temperature, softened unsalted butter.
Sugar: 4 cups or a 16-ounce bag of powdered sugar is needed. Do not worry about sifting it.
Tools: Ziploc bags (or a piping bag), sheet pans, parchment paper, a 9x5 inch loaf pan, and the shape of a heart cookie cutter.
HOW TO MAKE A RAINBOW HEART SURPRISE INSIDE CAKE
1. Preheat oven to 350° and line a large cookie sheet with parchment paper or wax paper.
2. In a large bowl, prepare one cake mix according to the instructions on the box. Divide cake batter equally into 5 separate bowls and add food coloring (5 different colors). Place into 5-gallon-sized plastic ziploc bags. Cut a small corner off of each bag.
3. Pipe colored batters into rows onto the lined pan. The rows should be touching.
4. Baking time - 8 to 10 minutes. Do not overbake. Let cool. Use a heart-shaped cookie cutter to cut your cake into mini heart cakes.
5. Grease a 9 by 5-inch loaf pan. Prepare batter from the other cake mix with no color. Pour a little bit of the white batter onto bottom of loaf pan. Line up your hearts (bottom of the heart down), so that they are standing upright and right next to each other. Pour the rest of the white cake mix batter on top and around the hearts. Bake for 45 minutes or until golden brown. Let cool.
6. Prepare the homemade frosting.
7. Frost the buttercream on top of the cake. Add rainbow sprinkles! Slice into the frosted cake to reveal this gorgeous heart shape cake!
• Food coloring: I recommend using food coloring gel. It is a better way to give your cake batter nice vibrant colors compared to regular food coloring drops.
• Colored batter: Feel free to use different colors or swirl around your rows before baking to give a cool effect to it!
• Piping: You can use a large Ziploc bag or piping bag to pipe the cake batter rows. Either work, I used ziploc bags. Cut a small corner off and if it is too small cut a little larger until you can pipe just enough, but not too much. You don't want the rows to be too thick.
• Heart cookie cutter: To cut each mini heart cake, use a small heart cookie cutter so it will fit in the loaf cake pan. If you prefer, make chocolate hearts with a chocolate cake mix instead of rainbow hearts.
• Mixer: Using a stand mixer makes it easier to make the frosting since you don't have to multi-task, but if you only have an electric mixer, that will do too! Both give the same and best results.
• Make it even cuter: If you have piping skills feel free to pipe some roses or a shell border on top with your favorite piping tip. Decorate however you want, Wilton tips offers many different varieties! You could also dye the frosting a different color if you like! A light pink frosting would be cute if you made this for Valentine's!
FREQUENTLY ASKED QUESTIONS
How do I store this cute easy recipe? If you want to store the cake as a whole, store it in a large Tupperware, or an airtight container, or wrap it with plastic wrap until sealed. Another way of storing it is by cutting individual slices and wrapping each one with plastic wrap to keep it fresh. Store at room temperature for a few days or in the fridge for a week.
What if my frosting is too thick? If your buttercream frosting is too thick, add more milk to it, one tablespoon at a time until it reaches the right consistency.
How do I know that the cake is fully done? To test that the cake is fully baked when you take it out of the oven, insert a toothpick in the center of the cake. If it comes out clean that means it is ready! If it comes out with wet batter, then it needs more time.
Can I make this gluten-free? Yes! I recommend using the King Arthur Vanilla Mix.
Where can I buy Amanda's book called Surprise-Inside Cakes? The book is available now on Amazon.com.
More cute holiday recipes
Rainbow Heart Surprise-Inside Cake
For the Cake
- 2 boxes white cake mix prepared according to package instructions*
- Food coloring of your choice
- *Note - keep the cake batters in 2 separate bowls. One will be colored, the other stays white.
For the cake
- Preheat oven to 350°F. Prepare one of the cake mixes according to the package instructions. Add the food coloring of your choice and mix well. I used 5 different colors. You can decide how many colors you want, then divide your batter accordingly. Place the colored batter in gallon sized resealable plastic bags, cut a small corner and pipe the batter in rows onto a parchment lined large cookie sheet. The rows should be touching. Then bake for about 8-10 minutes. Do not overbake. Let cool completely. Use a heart shaped cookie cutter to cut your cake into cookies.
- Prepare the batter from the other cake mix with no color. Pour a little in the bottom of a greased 9"x5" loaf pan. Line up your cookies, so that they are standing upright and right next to each other. They should be touching. Keep adding cookies until the pan is full of cookies from left to right. Pour the rest of the batter over the top of your colorful cookies. Bake for about 45 minutes or until golden brown. Let cool. Frost the cake with buttercream frosting. Add sprinkles for more color and have fun cutting into this beauty!
For the frosting
- Place shortening in large bowl and beat with an electric mixer on medium high for two minutes. Add the butter and beat until combined. With the mixer on low speed, gradually add half the sugar. Add the milk and vanilla. Beat on low for a few seconds. Keep mixer on low and add the remaining sugar. Cover mixer with a cloth, turn the mixer up to medium high and beat for 2 minutes. Add more milk if it's too thick.